Huang Yu-Wen, Tsai Hsiao-Chi, Wang Shih-Wei, Kuo Shu-Jui, Fong Yi-Chin, Tang Chih-Hsin
Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan.
Department of Medicine, Mackay Medical College, New Taipei City, Taiwan.
Cell Physiol Biochem. 2019;52(1):1-15. doi: 10.33594/000000001. Epub 2019 Feb 18.
BACKGROUND/AIMS: Chondrosarcoma is the second most common primary malignancy of bone, characterized by a high metastatic potential. Increasing clinical data highlight the important role played by lymphangiogenesis in cancer metastasis. Amphiregulin (AR) has been implicated in tumor metastasis and lymphangiogenesis, but its association with vascular endothelial growth factor-C (VEGF-C) expression and lymphangiogenesis in chondrosarcoma is unclear.
We used qPCR, ELISA and Western blotting to detect AR-induced VEGF-C expression in chondrosarcoma cells. Lymphangiogenesis was investigated by lymphatic endothelial cells (LECs) migration and tube formation. An in vivo experiment examined AR expression in tumor-associated lymphangiogenesis.
In this study, we found that both AR and VEGF-C expression correlated with tumor stage and were significantly higher than levels found in normal cartilage. Exogenous AR promoted VEGF-C expression in chondrosarcoma cells in a time- and dose-dependent manner and subsequently increased migration and tube formation of LECs. AR also increased VEGF-C expression and lymphangiogenesis through the Src/MEK/ERK/STAT3 signaling pathway. However, it is unclear as to how an EGFR ligand (AR) induces activation of the Src kinase. Knockdown of AR decreased VEGF-C expression in chondrosarcoma cells. Similarly, lymphangiogenesis was abolished in AR knockdown cells in an in vivo model of chondrosarcoma.
These results indicate that AR occurs through the Src/MEK/ERK/STAT-3 pathway, activating VEGF-C expression and contributing to lymphangiogenesis in human chondrosarcoma. Thus, AR could be a therapeutic target in metastasis and lymphangiogenesis of chondrosarcoma.
背景/目的：软骨肉瘤是第二常见的原发性骨恶性肿瘤，具有较高的转移潜能。越来越多的临床数据凸显了淋巴管生成在癌症转移中所起的重要作用。双调蛋白（AR）与肿瘤转移和淋巴管生成有关，但其与软骨肉瘤中血管内皮生长因子C（VEGF-C）表达及淋巴管生成的关联尚不清楚。
我们运用qPCR、ELISA和蛋白质印迹法检测AR诱导软骨肉瘤细胞中VEGF-C的表达。通过淋巴管内皮细胞（LEC）迁移和管腔形成来研究淋巴管生成。一项体内实验检测了AR在肿瘤相关淋巴管生成中的表达。
在本研究中，我们发现AR和VEGF-C的表达均与肿瘤分期相关，且显著高于正常软骨中的水平。外源性AR以时间和剂量依赖性方式促进软骨肉瘤细胞中VEGF-C的表达，随后增加LEC的迁移和管腔形成。AR还通过Src/MEK/ERK/STAT3信号通路增加VEGF-C的表达和淋巴管生成。然而，尚不清楚表皮生长因子受体（EGFR）配体（AR）如何诱导Src激酶激活。敲低AR可降低软骨肉瘤细胞中VEGF-C的表达。同样，在软骨肉瘤体内模型中，AR敲低细胞中的淋巴管生成被消除。
这些结果表明，AR通过Src/MEK/ERK/STAT-3途径发挥作用，激活VEGF-C表达并促进人软骨肉瘤中的淋巴管生成。因此，AR可能是软骨肉瘤转移和淋巴管生成的治疗靶点。
